A test method for residual stress of heat-resistant steel pipes for ultra-supercritical boilers

An ultra-supercritical boiler, residual stress technology, applied in the direction of force/torque/work measuring instrument, measuring force, measuring device, etc., can solve problems such as unsuitable for austenitic heat-resistant steel pipes

Active Publication Date: 2018-11-20
ZHONGBEI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional method of ultrasonic testing of plates and other planes is not suitable for measuring steel pipes, let alone austenitic heat-resistant steel pipes
[0006] However, in the prior art, ultrasonic waves have not been used to test the residual stress of heat-resistant steel pipes for ultra-supercritical boilers, especially for austenitic heat-resistant steel pipes.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A method for residual stress testing of heat-resistant steel pipes for ultra-supercritical boilers using ultrasonic waves. The specific method is: use the emitted polarized wave probe, set a coupling device, and the coupling device can be coupled with the outer surface of the steel pipe, and can firmly fix the probe; introduce the ultrasonic incident wave with frequency F to the surface of the steel pipe, and adjust the ultrasonic incident The excitation angle of the wave, the amplitude of the incident and outgoing waves is measured by a detector, and the residual stress is calculated and determined according to the incident time, exit time, and frequency / wavelength.

[0020] The beneficial effect of the invention is that it can be measured without damage and is suitable for measuring the steel pipe with curvature.

Embodiment 2

[0022] When the applicant adopts the method of Embodiment 1 to detect the residual stress of ordinary steel pipes, the common ultrasonic frequency is selected to be 15-35 MHz. The measured residual stress is basically consistent with the residual stress measured by the blind hole method, and the error range is within a reasonable range without correction.

Embodiment 3

[0024] When the applicant adopts the method of Example 1 to detect the residual stress of the austenitic heat-resistant steel pipe, the common ultrasonic frequency of 15-35 MHz is also selected. The measured residual stress has a large deviation from the residual stress measured by the blind hole method, and the results need to be Fitting is carried out, but the fitting result is shown as nonlinear fitting, which greatly weakens the applicability of this method in the detection of residual stress of austenitic heat-resistant steel pipes.

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PUM

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Abstract

The invention relates to a residual stress test method for a heat-resistant steel tube used for an ultra-supercritical boiler. The residual stress test method comprises the following steps that a coupling device is arranged by using a transmitting polarization wave probe, and the coupling device can be coupled with the external surface of the steel tube and the probe can be firmly fixed; and ultrasonic incident waves with frequency F are introduced to the surface of the steel tube, the excitation angle of the ultrasonic incident waves is adjusted, the amplitude of incident and emergent waves is measured by using a detector, and residual stress is determined through reckoning according to incident time, emergent time and the frequency / wavelength, wherein the heat-resistant steel tube is an austenitic heat-resistant steel tube, and the ultrasonic frequency F is 51-54MHz. Lossless determination suitable for the steel tube with curvature can be performed by the method.

Description

technical field [0001] The invention relates to a method for residual stress, in particular to a method for testing residual stress of heat-resistant steel pipes for ultra-supercritical boilers. Background technique [0002] A supercritical boiler refers to a boiler whose outlet steam pressure is greater than the critical pressure of water, 22.1MPa, and whose operating temperature is higher than the critical temperature of water, 374°C. The ultra-supercritical boiler is a new type of boiler that uses higher pressure and temperature to improve the thermal efficiency of operation based on the supercritical boiler. For the definition of ultra-supercritical boilers, there is no unified delineation in the current world power industry. It is generally considered that boilers with steam pressure higher than 26MPa and steam temperature higher than 590°C are ultra-supercritical boilers. Austenitic heat-resistant steel pipes have attracted widespread attention for their high-temperat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L5/00G01L1/25
CPCG01L1/255G01L5/0047
Inventor 徐宏张新张国伟任霁萍毛洪奎
Owner ZHONGBEI UNIV
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